A Guide To Growing Mushrooms | Love The Garden

How to Grow Mushrooms

LifeofRyrie's picture
By Sarah Ryrie, Gardening Enthusiast
mushrooms growing in compost

One of the most magical episodes of 'Alice's Adventures in Wonderland' is the one where our heronine comes across a caterpillar sat on a mushroom. This mushroom isn't your standard button mushroom though as when Alice eats from one side she grows taller, and when she eats from the other side she shrinks. I am sure that when Alice woke from her reverie one of the first things she wondered was how to grow mushrooms. Read on to find out how to do just that (but, magic isn't guaranteed). 

How do Mushrooms Grow?

Mushrooms are a mysterious fungi and they always seem to appear in the most inconvenient of places such as the middle of the lawn (How to Prevent Mushrooms Growing in your Lawn). Mushrooms are the fruit of a fungus (called Mycelium) that grows underground, within trees or in decaying logs and so you rarely know they are there until they fruit. 

To start growing your own mushrooms you need to get hold of some mushroom spores. The spores are microscopic in size but contain the blueprint for new mushroom growth. A mature mushroom is said to contain up to 16 billion spores and so this gives us plenty of opportunity to propogate our own. 

Collecting Spores

It is relatively easy to collect your own spores as all you need is a mushroom, some paper and a glass. Carefully remove the stem from the mushroom and gently remove any skirt that may be present protecting the gills in the mushroom head. To take the spore print all you need is the top of the mushroom with the gills exposed on the underside. Place the mushroom with the gills face down onto the paper and pop a glass over the top. Leave this for 24 hours. When you return, remove the glass and gently lift the mushroom. The spores will have fallen from the cap and you should see a print on the paper, which replicates the gill pattern from the mushroom. This is the spore print which can then be used to grow your own mushrooms. Keep the print in a sealed bag in a cool, dry, dark place until you are ready to cultivate.

Different parts of a mushroom spore kit

Image Credit: www.spores101.com

Cultivating Spores

Assuming that you have a spore print (after following the above instructions) you can use it to cultivate and grow your mushrooms. This can be done by creating a spore syringe, where the spores are re-hydrated using sterile water and then used to inoculate the growing medium. To create a spore syringe you need to work in a sterilised environment and with distilled water that has been boiled 2 or 3 times to ensure that any bacteria has been eliminated. Make sure that your syringe needle is sterile by holding it in a flame for a few seconds. Draw some of the cooled, sterilised water into the syringe body. Using the syringe needle, lightly scrap the spores from your spore print into a sterilised glass. Expunge half of the water from the syringe into the glass. Draw the spore water back into the syringe. At this point you should notice that the water has become slightly discoloured and you may even be able to see some floating clusters of spores. This spore water can then be used to inocluate your growing medium. 

Germinating Spores

As the spores don't contain chlorophyll they feed off substances other than light to gain the nourishment they need to germinate. Suitable materials range from sawdust and straw to wooden plugs and grain. The variety of mushroom dictates the most suited material as different types of mushroom grow in different materials (the substrate) from straw to wood chips. Blending together the spores and the nutrients provided by the suited substance is known as the spawn. The spawn allows the mycelium to develop. The mycelium is the fungus from which mushrooms emerge during fruiting. When the spawn is mixed with a substrate fruiting tends to be more vigorous and mushrooms are more plentiful. 

Mushroom Growing Kits

Mushrooms from grow your own box being harvested

Image Credit: www.grocycle.com

As can be seen, there are lots of stages in growing mushrooms, which can be tricky for a novice, which is why it's a good idea to start growing mushrooms at home with a Grow Your Own Mushrooms kit. The mushroom growing kits can be purchased according to the type of mushrooms you wish to grow and contain everything you need to successfully grow your own mushrooms.

Oyster mushrooms grow on straw and so a kit for this variety would include a breathable bag of straw, mushroom spawn and a bag tie. Button mushrooms like to grow in a tray of composted manure and this would be the substrate included in your kit. Shiitake mushrooms grow on wood and are supplied in a specially created growing block (or log) which contains all the nutrients required for a successful shiitake harvest.  Full instructions are usually included in the kits. 

Different Types of Mushrooms

There are over 14,000 different types of mushrooms, many poisonous and many deliciously edible. Some of the more popular varieties can be grown at home by following a few simple instructions.

Wood loving mushrooms include Oyster, Shiitake and Lion's Mane to name the more popular varieties. Compost lovers include the Button and Portobello varieties. 

Growing Oyster Mushrooms (Pleurotus Ostreatus)

Pearl oyster mature mushroom groing on a tree stump

Image Credit: www.gourmetmushrooms.co.uk

Oyster mushrooms are among the more colourful varieties of mushrooms and in the wild are found helping with the decomposition of dead trees. You can grow oyster mushrooms at home and if you invest in a kit, it will more than likely include a perforated bag of straw that has been innoculated with oyster mushroom spawn and already has some degree of mycelium developing. The kit should be kept moist or in a humid environment and will usually fruit twice. After the second harvest any remaining mycelium could be used to inoculate an additional growing medium.

Oyster mushrooms prefer to be grown on logs, or in dead trees, and you can recreate this by using a hardwood log and dowel spawn. Most hardwoods can be used although apple, sycamore and ash are not recommended. Ensure that the log was cut from a healthy tree and not more than 6 weeks previously. Equally if you already have mycelium from an Oyster mushroom kit, you could drill 10mm holes at regular intervals along the log and carefully insert the left over mycelium. Keep moist and regulate the temperature, in 6-12 months the mycelium should have taken hold over the log and be ready to fruit. If the mycelium has grown into the log it will continue to fruit until all available nutrients have been used in the decaying log.

Growing Oyster mushrooms can be done by mixing the spawn with some sawdust, used coffee grounds and straw. Place the mixture in a plastic bag and leave in a cool dark environment. It may take a few months but fruiting should occur. 

Growing Shiitake Mushrooms (Lentinula Edodes)

Shiitake mushrooms growing on a tree

Image Credit: www.homefarmer.co.uk

Growing Shiitake mushrooms can be done in the same way as Oyster mushrooms and as part of a kit you will be supplied with wooden dowels that have been impregnated with the Shiitake mycelium. These wooden dowels are then inserted into a hardwood log that has been prepared by drilling holes at 6 inch intervals along the length of the log. Once the dowels have been inserted they are sealed using wax which ensures that the dowel spawn doesn't dry out. 

Shiitake mushrooms can also be grown on blocks of sterilised sawdust. Fruiting is likely to happen quicker by using this growing medium rather than a hardwood log, but the quality of the mushroom will not be as good. 

Growing White Cap (Button) Mushrooms (Agaricus Bisporus)

White button mushrooms growing in the ground

Image Credit: www.kingsseeds.com

Growing button mushrooms is the most straightforward of all methods and Agaricus Bisporus also includes the popular, nutty, Portobello (or brown cap) mushrooms. Kits for these varieties will include a tray and lid and a pre-spawned substrate or compost. If you don't buy a kit then follow the instructions above to create your own spore print, and spore syringe with which you will be able to  inoculate the compost.  

For best results make your compost out of a mixture of horse manure and wet straw. Mix the two together and pack down tightly to allow the temperature in the manure to rise. Turn this mixture every couple of days for 2 or 3 weeks to allow the manure to rot down and concentrate the nutrients required for mushroom growing. When the mixture is dark brown and sweet smelling then you have a great compost. 

Put enough compost in a tray to cover to a depth of about 3 inches then spray over the spore syringe to inoculate. Mix again and cover with a damp newspaper.  In 2-3 weeks the mycelium should be showing signs of growth. Once the tray has become covered with the tiny white threads of the mycelium, then wet and cover with a layer of casing which can be made of peat free compost with 2 or 3 handfuls of lime. Keep the casing moist and the air temperature warm and fruiting should begin in 3-4 weeks.

Have you grown your own mushrooms? What variety have you found easiest? 

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